/* STEEL PANEL — лендинг по структуре сэндвич-панели-сибирь.рф.
   Белые секции, тёплый янтарный акцент клиента, фото первого экрана с затемнением. */
:root{
  --ink:#23272B;
  --muted:#646B72;
  --bg:#FFFFFF;
  --soft:#F5F6F7;
  --line:#E4E7EA;
  --accent:#F6AE3C;
  --accent-h:#EC9E22;
  --dark:#24292E;
  --serif:"PT Serif",Georgia,"Times New Roman",serif;
  --sans:"PT Sans",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
  --gut:max(16px,env(safe-area-inset-left,0px));
  --gut-r:max(16px,env(safe-area-inset-right,0px));
  --hdr:68px;
  color-scheme:light;
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:calc(var(--hdr) + 12px);-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:18px/1.55 var(--sans);overflow-x:clip}
img{max-width:100%;height:auto;display:block}
a{color:inherit}
button,input,textarea{font:inherit;color:inherit}
h1,h2,h3,p{margin:0}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--accent-h);outline-offset:3px}
.wrap{max-width:1180px;margin:0 auto;padding-left:var(--gut);padding-right:var(--gut-r)}
.wrap.narrow{max-width:900px}
.muted{color:var(--muted)}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{transition:none!important;animation:none!important}}

/* кнопки */
.btn{display:inline-flex;align-items:center;justify-content:center;min-height:52px;padding:0 28px;border:0;border-radius:8px;background:var(--accent);color:#1E1E1E;font-weight:700;font-size:16px;cursor:pointer;text-decoration:none;white-space:nowrap;transition:background-color .2s,transform .1s}
.btn:hover{background:var(--accent-h)}
.btn:active{transform:translateY(1px)}
.btn-sm{min-height:42px;padding:0 18px;font-size:15px}
.btn-wide{width:100%}
.btn-dark{background:var(--dark);color:#fff}
.btn-dark:hover{background:#111}
.btn[disabled]{opacity:.6;cursor:wait}

/* шапка */
.hdr{position:sticky;top:0;z-index:40;background:#fff;border-bottom:1px solid var(--line);padding-top:env(safe-area-inset-top,0px)}
.hdr-in{height:var(--hdr);display:flex;align-items:center;gap:28px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;font:700 19px/1 var(--sans);letter-spacing:.06em;margin-right:auto}
.logo img{height:52px;width:auto}
.nav{display:flex;gap:24px;font-size:15px}
.nav a{text-decoration:none;color:var(--ink)}
.nav a:hover{color:var(--accent-h)}
.burger{display:none;width:44px;height:44px;border:1px solid var(--line);border-radius:8px;background:#fff;cursor:pointer;flex-direction:column;justify-content:center;align-items:center;gap:5px}
.burger i{display:block;width:18px;height:2px;background:var(--ink)}
@media (max-width:1060px){
  .nav{position:absolute;left:0;right:0;top:100%;background:#fff;border-bottom:1px solid var(--line);flex-direction:column;gap:0;padding:8px var(--gut-r) 16px var(--gut);display:none}
  .nav.open{display:flex}
  .nav a{padding:12px 0;border-bottom:1px solid var(--line);font-size:17px}
  .burger{display:flex}
}
@media (max-width:520px){.hdr .btn-sm{display:none}.logo img{height:44px}}

/* первый экран */
.hero{position:relative;color:#fff;background:#2b2f33 url(../img/hero.jpg) center/cover no-repeat}
.hero::before{content:"";position:absolute;inset:0;background:linear-gradient(90deg,rgba(20,22,25,.82) 0%,rgba(20,22,25,.62) 55%,rgba(20,22,25,.45) 100%)}
.hero-in{position:relative;display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,.75fr);gap:48px;align-items:center;padding-block:clamp(48px,7vw,96px)}
@media (max-width:900px){.hero-in{grid-template-columns:minmax(0,1fr);gap:32px}}
.hero h1{font:700 clamp(32px,4.4vw,52px)/1.12 var(--serif);text-wrap:balance}
.hero h1 span{display:block;color:var(--accent);margin-top:6px}
.hero-points{list-style:none;padding:0;margin:26px 0 0;display:grid;gap:8px;font:700 clamp(20px,2.2vw,28px)/1.25 var(--serif)}
.hero-lead{margin-top:24px;max-width:60ch;color:rgba(255,255,255,.82);font-size:17px}

/* формы */
.form{display:grid;gap:14px;background:#fff;border:1px solid var(--line);border-radius:12px;padding:28px;color:var(--ink)}
.form-dark{background:rgba(36,41,46,.92);border-color:rgba(255,255,255,.08);color:#fff}
.form-title{font:700 21px/1.3 var(--serif)}
.field{display:grid;gap:6px}
.field>span{font-size:13px;letter-spacing:.04em;text-transform:uppercase;color:var(--muted)}
.form-dark .field>span{color:rgba(255,255,255,.7)}
.field input,.field textarea{width:100%;border:1px solid #CFD4D9;border-radius:8px;background:#fff;color:var(--ink);padding:12px 14px;font-size:16px;line-height:1.3}
.field textarea{resize:vertical;min-height:84px}
.form-dark .field input,.form-dark .field textarea{background:rgba(255,255,255,.08);border-color:rgba(255,255,255,.18);color:#fff}
.field input::placeholder,.field textarea::placeholder{color:#9AA1A7}
.field input:focus,.field textarea:focus{outline:none;border-color:var(--accent)}
.field input.bad{border-color:#D9534F}
.consent{display:flex;gap:10px;align-items:flex-start;font-size:14px;line-height:1.4;color:var(--muted);cursor:pointer}
.form-dark .consent{color:rgba(255,255,255,.75)}
.consent input{width:18px;height:18px;margin:1px 0 0;flex:none;accent-color:var(--accent-h)}
.consent a{color:inherit}
.consent.bad{color:#D9534F}
.form-dark .consent.bad{color:#FFB4A8}
.hp{position:absolute;left:-9999px;width:1px;height:1px;opacity:0}
.form-msg{font-size:15px;min-height:0}
.form-msg.err{color:#D9534F}
.form-dark .form-msg.err{color:#FFB4A8}
.form-done{display:grid;gap:8px;text-align:center;padding:12px 0}
.form-done b{font:700 22px/1.3 var(--serif)}

/* полоса преимуществ */
.usp{background:var(--dark);color:#fff}
.usp-in{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:0}
.usp-in>div{display:grid;gap:4px;padding:22px 20px;border-left:1px solid rgba(255,255,255,.1)}
.usp-in>div:first-child{border-left:0;padding-left:0}
.usp b{color:var(--accent);font-size:17px}
.usp span{font-size:15px;color:rgba(255,255,255,.75);line-height:1.4}
@media (max-width:900px){.usp-in{grid-template-columns:repeat(2,minmax(0,1fr))}.usp-in>div:nth-child(3){border-left:0;padding-left:0}.usp-in>div:nth-child(n+3){border-top:1px solid rgba(255,255,255,.1)}}
@media (max-width:520px){.usp-in{grid-template-columns:minmax(0,1fr)}.usp-in>div{border-left:0;padding-left:0}.usp-in>div+div{border-top:1px solid rgba(255,255,255,.1)}}

/* секции */
.sec{padding-block:clamp(56px,7vw,96px)}
.sec-soft{background:var(--soft)}
.sec h2,.why h2{font:700 clamp(28px,3.4vw,40px)/1.2 var(--serif);text-align:center;text-wrap:balance;margin-bottom:clamp(28px,4vw,48px)}
.sec h2.h2-left{text-align:left;margin-bottom:16px}
.sub{text-align:center;color:var(--muted);margin:-28px 0 36px}
.badge{display:inline-block;vertical-align:middle;margin-left:8px;font:700 14px/1 var(--sans);letter-spacing:.04em;text-transform:uppercase;background:var(--accent);color:#1E1E1E;padding:7px 10px;border-radius:6px}
.sec-cta{display:flex;justify-content:center;margin-top:36px}

/* карточки товаров */
.cards{display:grid;gap:20px}
.cards-3{grid-template-columns:repeat(3,minmax(0,1fr))}
.cards-2{grid-template-columns:repeat(2,minmax(0,1fr))}
.cards-center{max-width:780px;margin:20px auto 0}
.cards-3+.cards-2{margin-top:20px}
@media (max-width:860px){.cards-3{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:520px){.cards{gap:10px}.cards-3+.cards-2,.cards-center{margin-top:10px}.cards .card-img{height:140px;padding:10px}.cards .card-img.tall{height:190px}.cards .card figcaption{font-size:15px;padding:10px 8px 12px;line-height:1.3}}
.card{margin:0;background:#fff;border:1px solid var(--line);border-radius:12px;overflow:hidden;display:flex;flex-direction:column}
.card-img{height:220px;display:flex;align-items:center;justify-content:center;padding:18px;background:#fff}
.card-img.tall{height:300px}
.card-img img{max-height:100%;max-width:100%;width:auto;height:auto;object-fit:contain}
.card figcaption{padding:14px 18px 20px;text-align:center;font-size:19px;border-top:1px solid var(--line)}

/* техкарта */
.tech{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:40px;align-items:center;background:#fff;border:1px solid var(--line);border-radius:12px;padding:28px}
.tech img{margin:0 auto}
.tech dl{margin:0;display:grid;grid-template-columns:auto minmax(0,1fr);gap:14px 24px;font-size:18px}
.tech dt{color:var(--muted)}
.tech dd{margin:0;font-weight:700}
@media (max-width:760px){.tech{grid-template-columns:minmax(0,1fr)}}

/* договор */
.contract{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:48px;align-items:center}
.contract>div{display:grid;gap:18px;justify-items:start}
.contract img{border-radius:12px}
@media (max-width:860px){.contract{grid-template-columns:minmax(0,1fr)}.contract img{order:-1}}

/* почему мы */
.why{position:relative;padding-block:clamp(56px,7vw,96px);color:#1E1E1E;background:#F3B04A url(../img/why-bg.jpg) center/cover no-repeat}
.why::before{content:"";position:absolute;inset:0;background:rgba(246,174,60,.88)}
.why .wrap{position:relative}
.why-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:28px 48px;max-width:960px;margin:0 auto}
@media (max-width:700px){.why-grid{grid-template-columns:minmax(0,1fr)}}
.why-grid>div{display:flex;gap:16px;align-items:flex-start}
.why-grid b{display:block;font:700 21px/1.25 var(--serif);margin-bottom:4px}
.why-grid span{font-size:16px;line-height:1.45}
.tick{flex:none;width:36px;height:36px;border-radius:50%;background:#fff;position:relative}
.tick::after{content:"";position:absolute;left:13px;top:9px;width:8px;height:14px;border:solid var(--accent-h);border-width:0 3px 3px 0;transform:rotate(45deg)}

/* галерея */
.gallery{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
@media (max-width:860px){.gallery{grid-template-columns:repeat(2,minmax(0,1fr))}}
.gallery button{padding:0;border:0;background:none;cursor:zoom-in;border-radius:10px;overflow:hidden;aspect-ratio:4/3}
.gallery img{width:100%;height:100%;object-fit:cover;transition:transform .4s}
.gallery button:hover img{transform:scale(1.03)}
.objects{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}
.objects img{border-radius:12px;aspect-ratio:4/3;object-fit:cover;width:100%}
@media (max-width:520px){.objects{grid-template-columns:minmax(0,1fr)}}

/* шаги */
.steps{list-style:none;counter-reset:s;padding:0;margin:0;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:32px}
.steps li{counter-increment:s;display:grid;gap:8px;text-align:center;align-content:start}
.steps li::before{content:counter(s,decimal-leading-zero);font:700 44px/1 var(--sans);color:var(--ink)}
.steps b{font:700 21px/1.3 var(--serif)}
.steps span{font-size:16px;color:var(--muted)}
@media (max-width:760px){.steps{grid-template-columns:minmax(0,1fr)}}

/* отзывы */
.reviews{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}
@media (max-width:760px){.reviews{grid-template-columns:minmax(0,1fr)}}
.rv{background:#fff;border:1px solid var(--line);border-radius:12px;padding:26px;display:grid;gap:12px;align-content:start}
.rv b{font:700 20px/1.3 var(--serif)}
.rv p{font-size:16px;line-height:1.55;color:#3A3F44}

/* вопросы */
.faq{display:grid;gap:12px}
.faq details{background:#fff;border:1px solid var(--line);border-radius:10px}
.faq summary{list-style:none;cursor:pointer;padding:18px 52px 18px 22px;position:relative;font-weight:700;font-size:17px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";position:absolute;right:20px;top:12px;font-size:28px;font-weight:400;color:var(--accent-h);transition:transform .2s}
.faq details[open] summary::after{transform:rotate(45deg)}
.faq details p{padding:0 22px 20px;color:var(--muted);font-size:16px}

/* контакты */
.contacts{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:48px;align-items:start}
@media (max-width:860px){.contacts{grid-template-columns:minmax(0,1fr)}}
.contacts dl{margin:0;display:grid;gap:6px}
.contacts dt{font-size:13px;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);margin-top:12px}
.contacts dt:first-child{margin-top:0}
.contacts dd{margin:0;font-size:20px}

/* подвал */
.ftr{border-top:1px solid var(--line);padding-block:24px;font-size:14px;color:var(--muted)}
.ftr-in{display:flex;flex-wrap:wrap;gap:8px 24px;justify-content:space-between}
@media (max-width:760px){.ftr{padding-bottom:calc(92px + env(safe-area-inset-bottom,0px))}}

/* мобильная кнопка */
.mcta{display:none}
@media (max-width:760px){
  .mcta{display:block;position:fixed;left:0;right:0;bottom:0;z-index:30;background:rgba(255,255,255,.97);border-top:1px solid var(--line);padding:10px var(--gut-r) calc(10px + env(safe-area-inset-bottom,0px)) var(--gut);transition:transform .25s}
  .mcta.off{transform:translateY(110%)}
}

/* модальные окна */
.modal{border:0;border-radius:14px;padding:0;width:min(460px,calc(100vw - 24px));max-height:calc(100dvh - 24px)}
.modal::backdrop,.lightbox::backdrop{background:rgba(20,22,25,.6)}
.modal .form{border:0;position:relative;padding:30px 26px 26px}
.modal-text{font-size:15px;margin-top:-6px}
.modal-x{position:absolute;top:10px;right:10px;width:40px;height:40px;border:0;border-radius:50%;background:var(--soft);font-size:22px;cursor:pointer;z-index:2}
.lightbox{border:0;padding:0;background:transparent;max-width:min(1100px,calc(100vw - 24px));max-height:calc(100dvh - 24px)}
.lightbox img{max-height:calc(100dvh - 24px);border-radius:10px}

/* появление при прокрутке */
.js .reveal{opacity:0;transform:translateY(24px);transition:opacity .7s ease,transform .7s ease}
.js .reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){.js .reveal{opacity:1;transform:none}}